Kinetics and Mechanism of Thermal Decomposition of Bis(η3-Allyl)Nickel Complexes

Kinetics and Catalysis - The kinetics of thermal decomposition of bis(η3-allyl) nickel complexes in various media is studied. The specific features of the mechanism are determined, including...     

Thermal Stability and Decomposition Kinetics of the β-CD Cinnamic Aldehyde Inclusion Complex

The stability of the -CD cinnamic aldehyde inclusion complex wasinvestigated by TG and DSC. The weight loss takes place in three stages:dehydration occurs at 50–120 °C; the dissociationof -CDC₉H₈O occurs at 200–260 °C;and the decomposition of -CD begins at 280 °C. Thekinetics of the dissociation of cinnamic aldehyde from the -CD cavitywere studied by means of thermogravimetry both at constant temperatureand linear increasing temperature. The results show that the dissociationof -CDC9H8O is dominated by a one-dimensional diffusionprocess. The activation energy, E, is 160 kJmol-1. Thepre-exponential factor A is 5.8 × 1014 min-1.     

Thermal Decomposition Kinetics of Triethylene Glycol Dinitrate

Introduction Triethylene glycol dinitrate (TEGDN) is a novel en-ergetic material containing two groups of NO2, which can be used as an energetic plasticizer ingredient in propellants because of its excellent proformance.1 It exhibits lower impact sensitivity, better thermostability, weaker poisonousness and volatility, and stronger effec-tiveness of plasticizing cellulose nitrate than nitroglyc-erine (NG). As a new plasticizer TEGDN has good ap-plication prospects in the near future. The…     

Kinetics and Mechanism of the Exothermic First-stage Decomposition Reaction of Dinitroglycoluril

Introduction Dinitroglycoluril (DINGU) is a typical cyclourea nitramine. Its crystal density is 1.94 gcm-3. The detonation velocity corresponding to =1.94 gcm-3 is about 8450 ms-1. Its sensitivity to impact is better than that of cyclotrimethylenetrinitramine. It has the potential for possible use as high explosive from the point of view of the above-mentioned high performance. Its preparation,1-4 properties1-4 and hydrolytic behavior4 have been reported. In the present paper, we report i…     

Thermal Characterization and Decomposition Kinetics of Free Anthraquinones from Rhubarb

Rhubarb is an important Chinese traditional medicine and its genins such as aloe-emodin have been widely used in the field of antibacterial, antivirus, antitumor and antibacterial immunity1,2. Chrysophanol and physcion are the effective components for dec…     

Kinetics and Mechanism of the Thermal Decomposition Reaction of 3,3-Bis（azidomethyl）oxetane／Tetrahydrofuran Copolymer

Introduction 3,3-Bis(azidomethyl)oxetane/tetrahydrofuran (BAM- O/THF, marked as B/T) copolymer can be used as an azide binder of high energy propellants with the lower signature, and lower sensitivity to improve the me-chanical properties at lower temperature and the burning rate characteristics. Its decomposition kinetics and the effects of THF on the decomposition kinetics of BAMO copolymers have been reported.1,2 In the present work, we report the kinetic model function and kinetic pa…     

Kinetics and Mechanism of Decomposition of the β-Chlorovinyl and β-Iodovinyl Complexes of Platinum(IV) in Aqueous Iodide Solutions

It was found that the -iodovinyl and -chlorovinyl complexes of platinum(IV) undergo decomposition in acidic aqueous solutions in the presence of NaI (2.5 M) with the simultaneous formation of acetylene and a corresponding vinyl halide RX (X = Cl, I). The kinetics and the composition of products are consistent with a mechanism that includes an equilibrium step of the reduction of the -halovinyl complexes of Pt(IV) by iodide ions to form corresponding Pt(II) derivatives; the degradation of the above organoplatinum compounds by halogen -elimination to form acetylene; and a step of the protodemetallation of the -vinyl derivatives of Pt(II), which leads to RX. The rate constants of individual steps and the equilibrium constant were estimated.     

Synthesis, Characterization and Thermal Decomposition Mechanism of Cetyltrimethyl Ammonium Tetrathiotungstate

The synthesis, characterization and thermal decomposition mechanism of cetyltrimethyl ammonium tetrathiotungstate （CTriMATT） were studied herein. The as-synthesized CTriMATT was characterized by Elemental analysis, X-ray diffraction （XRD）, Fourier transform infrared （FT-IR）, Ultraviolet visible （UV-Vis） spectra. The results showed that the as-synthesized CTriMATT had high purity and good crystallinity. The introduction of alkyl groups induced a shift of the stretching vibration band of W-S bond to lower wavenumber, while it had no influence on the position of WS4^2-. Thermogravimetric analysis （TG）, differential thermal analysis （DTA） and in situ XRD characterizations revealed that CTriMATT began to decompose at 423 K in nitrogen and was converted to WS2 eventually. In addition, the decomposition product of CTriMATT at 673 K in nitrogen was characterized by N2 adsorption （BET） and scanning electron microscopy （SEM）. The results demonstrated that WS2 with higher specific surface area, and pore volume could be obtained from the thermal decomposition of CTriMATT in nitrogen.     

Synthesis, Characterization, Thermal Decomposition Mechanism and Non-Isothermal Kinetics of the Pyruvic Acid-Salicylhydrazone and Its Complex of Praseodymium(III)

IntroductionHydrazonesactasherbicides,insecticides,nemato cides ,rodenticidesandplantgrowthregulators.Theyshowspasmolyticactivity ,hypotensiveactionandactivityagainstleukaemia,sarcomasandothermalignantneoplasm .1Rareearthelementshavestrongbiologicaleffectandmanycom plexesofrareearthshaveallkindofmedicinalactivities.2 Aseriesof 2 oxopropionyl(pyridine 4 fomyl)hydrazonewithrareearthscomplexeswassynthesizedbyYangandtheEucom plexshowedacertainanticanceractivity .3Therearethreeradicalsinthepyru…     

Thermal Decomposition Kinetics and Mechanism of Tb(Ⅲ) m-Methylbenzoate Complex with 1,10-Phenanthroline in Static Air Atmosphere

IntroductionThe rare- earth carboxylic acid complexes havemany special structures and interesting spectro-scopic properties,which are of great interestin ex-traction,separation,germicide preparation,catal-ysis,luminescence and functional material prepara-tion.The preparation,crystal structure,fluores-cence spectroscopy and thermal properties of somerare- earth carboxylic acid complexes have beenstudied[1— 8] . In this work,on the basis of thestructural and fluorescence spectroscopicresearches…     

Kinetics of the Thermal Decomposition of Magnesium Salicylate Powder in Air

IntroductionThe chelate complexes of salicylic acid with rareearth and alkali earth ions have attracted considerableattention because of their special antibacterial proper-ties[1—3].The study of the thermal degradation of metalsalicylates is of major int…     

Kinetics and Mechanism of Exothermic First-stage Decomposition Reaction of 2,6-Bis （2,2,2-trinitroethyl）glycoluril

The thermal behavior, mechanism and kinetic parameters of the exothermic first-stage decomposition of the title compound in a temperature-programmed mode were investigated by means of DSC, TG-DTG and IR. The reaction mechanism was proposed. The kinetic model function in differential form, apparent activation energy(Ea) and pre-exponential factor(A) of this reaction are (3/2)(1-a)[-ln(1-a)]1/3, 185.52 kJ/mol and 1017.78 s-1, respectively. The critical temperature of the thermal explosion of the compound is 201.30 ℃. The values of ΔS≠, ΔH≠ and ΔG≠ of this reaction are 72.46 J/(mol · K), 175.1 kJ/mol and 141.50 kJ/mol, respectively.     

Synthesis and Thermal Decomposition Kinetics of the Complex of Samarium p-Methylbenzoate with 1 ,10-Phenanthroline

The complex [Sm（p-MBA）3phen]2 （p-MBA, p-methylbenzoate; phen, 1,10-phenanthroline） was prepared and characterized by elemental analysis, IR and UV spectra. The thermal decomposition process of [Sm（pMBA）3phen]2 was studied under a static air atmosphere by TG-DTG and IR techniques. Thermal decomposition kinetics was investigated employing a newly proposed method, together with the integral isoconversional non-finear method. Meanwhile, the thermodynamic parameters （AH#, △G# and AS#） were also calculated. The lifetime equation at mass-loss of 10% was deduced as In r=-24.7825＋ 18070.43/T by isothermal thermogravimetric analysis.     

The Preparation of Perovskite Nano Powder by Sol-gel from DTPA and the Mechanism of Thermal Decomposition

Dy0.8Sr0.2FeO3 nano powder, a synthetic oxide, is made by sol-gel method from metal nitrate and diethylenetriaminepentaaeetic acid (DTPA), and the processing parameters are optimized.The process of the preparation, thermal decomposition and the property of the powder are studied by TG-DTA, IR, TEM, and XRD. The diameter of the average grain is about 70 nm. This new technique can be used in the preparation and the studying of ha‘no materials in the complex oxide system.     

Synthesis,Characterization,Thermal Decomposition Mechanism and Non—Isothermal Kinetics of the Pyruvic Acid—Salicylhydrazone and Its Complex of Prasseodymium（Ⅲ）

The pyruvic add‐salicylhydrazone and its new complex of Pr(III) were synthesized. The formulae C₁₀H₁₀N₂O₄ (mark as H₃L) and [Pr₂(L)₂(H₂O)₂]·3H₂O (L= the triad form of the pyruvic acid‐salicylhydrazone [C₁₀H₇N₂O₄]^3‐) were determined by elemental and EDTA volumetric analysis. Molar conductance, IR, UV, X‐ray and ¹H NMR were carried out for the characterizations of the complex and the ligand. The thermal decompositions of the ligand and the complex with the kinetic study were carried out by non‐isothermal thermogravimetry. The Kissinger's method and Ozawa's method are used to calculate the activation energy value of the main step decomposition. The stages of the decompositions were identified by TG‐DTG‐DSC curve. The non‐isothermal kinetic data were analyzed by means of integral and differential methods. The possible reaction mechanism and the kinetic equation were investigated by comparing the kinetic parameters.     

Non-isothermal Kinetics of the Thermal Decomposition of 3-Nitro-1,2,4-triazol-5-one Magnesium Complex

Introduction3 Nitro 1,2 ,4 triazol 5 one (NTO)metalcomplexeshavemanyspecialstructuresandsomepotentialusesinammunition .1 4 Wepreviouslypreparedanddeterminedthecrystalstructureofitsmagnesiumcomplex ,5andinthispaper ,wediscusseditsthermalbehaviorbyDSCandTG/DTGtechniquesandstudieditsnon isothermalkineticsbythemeansoftheKissingermethod ,theOzawamethod ,thedifferentialmethodandtheintegralmethod .ExperimentalSample[Mg(H2 O) 6 ](NTO) 2 ·2H2 Owaspreparedasfollows :AcalculatedamountofMg(OH…     

Thermal Decomposition of Poly-α-methylstyrene

Kinetic studies on the decomposition of poly-α-methylstyrene samples with molecular weights ranging from 3.7 × 10³ to to 2.0 × 10⁵ have been carried out with the differential thermo-gravimetric technique. Changes in molecular weight distributions with decomposition, at different temperatures, have been studied by gel-permeation chromatography. A depolymeriza-tion mechanism was shown to be responsible for the decomposition phenomenon. The order of reaction for this depolymerization reaction was found to be one. The values of the activation energy for samples of different molecular weights showed no specific trends; however, it would appear that polymers with relatively higher molecular weights have lower activation energies of decomposition. The proportions of the three steric forms, viz., isotactic, heterotactic, and syndiotactic, in the polymer before and after thermal treatments did not change, suggesting that stereoregularity has no apparent effect on the decomposition of poly-α-methylstyrene.     

Thermochemical Properties and Decomposition Kinetics of Ammonium Magnesium Phosphate Monohydrate

Ammonium magnesium phosphate monohydrate NH4MgPO4·H2O was prepared via solid state reaction at room temperature and characterized by XRD, FT-IR and SEM. Thermochemical study was performed by an isoperibol solution calorimeter, non-isothermal measurement was used in a multivariate non-linear regression analysis to determine the kinetic reaction parameters. The results show that the molar enthalpy of reaction above is （28.795 ± 0.182） kJ/mol （298.15 K）, and the standard molar enthalpy of formation of the title complex is （-2185.43 ± 13.80） kJ/mol （298.15 K）. Kinetics analysis shows that the second decomposition of NH4MgPO4·H2O acts as a double-step reaction： an nth-order reaction （Fn） with n=4.28, E1=147.35 kJ/mol, A1=3.63×10^13 s^-1 is followed by a second-order reaction （F2） with E2=212.71 kJ/mol, A2= 1.82 × 10^18 s^-1.     

Synthesis, Crystal Structure and Kinetic Mechanism of Thermal Decomposition of a Zinc(II) Complex with N-Salicylidene-p-toluidine

1 INTRODUCTION Over the past decades, considerable attention has been devoted to the synthesis, characterization and property studies of Schiff bases and their com- plexes because of their potential and developed appli- cations in the fields of conducting and magnetic ma- terials, dyes, non-linear optics, catalysis, analytical chemistry, biochemical research, agriculture and so on[1～7]. A large number of reports are available in the chemistry and biologic activities of transition metal co…